The Intel® Dual Band Wireless-AC 8265 comes in two different versions. One that is meant for desktop and the other meant for laptops. Before we go any further, we would like to confirm which version you have. Please check these links below for additional information:

In this case, our best recommendation is for you to contact the manufacturer of the motherboard and/or laptop as they are the ones entitled to provide the information on which type of antennas are recommended. Please, take a look at this online advisory for additional information: Regulatory Information Regarding Hardware Installation or Upgrade

The antennas on the Intel® Dual Band Wireless-AC 8265 Desktop Kit are 2x2 and in the specification it means two antennas are used for transmitting and two for receiving. Since this is a combo, the antenna 1 is for Wi-Fi and Bluetooth and antenna 2 for Wi-Fi.

I bought the same card and plugged only into "1", and it works beautifully. I now get 2.4Ghz and 5Ghz, and it has great signal strength. My HP Laptop 15-BS015DX only came with 1 antenna wire, I bought an additional antenna and was going to route behind the screen with the other antenna but not going to now. It works great on the installed cable only.